Control system



June 1o, w1947. G. L. BORELL 2,422,162

CONTROL SYSTEM Filed Feb. 25, 1944 2 Sheets-Sheet 2 nventor Gioie/FL 50ML/- (Ittorneg 'Patented June 1o, i947 CONTROL SYSTEM George L. Borell, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware l Application February 25, 1944, Serial No. 523,872

This invention relates generally to control systems of the kind used in connection withI internal combustion engines, particularly aircraft engines, for selecting and controlling intake manifold pressures. The invention more particularly relates to a control system wherein over acceleration of the turbine driven compressor, used in such installations, is prevented.

The turbine and compressor operate usually at high speeds and not only must means be provided for limiting these spe ds to a safevalue, to prevent damage to the parts, but it is also necessary to provide means for limiting the rate of acceleration of the turbine. For example, if the waste gate is closed by operation of the pressure sensing means, in order to satisfy the call thereof for an increase in operating speed of the turbine and compressor due to a sharp decrease in intake manifold pressure below the selected value, there is a pronounced tendency for the Speed of the turbine to increase with such rapidity as to cause hunting of the controls and overshooting of the pressure such that the'pressure will fluctuate about the selected value, instead of remainingsubstantially constant. This is, of course, very undesirable.

It is the primary object of my invention to improve control systems of this kind by the provision of a system or means for eliminating the tendency toward over acceleration of the turbine and compressor as the waste gate is closed in the attempt to satisfy the call of the controls for an increase in intake manifold pressure, and thereby to prevent the undesirable hunting and overshooting tendencies of such systems.

Another object is to provide means for preventing over acceleration of the system by the very eiective, simple and positive method f causing the waste gate positioning motor to operate the waste gate at a slower speed or rate when closing it, than when it is being opened. Thus the turbine and compressor speed may be quickly reduced when the control system calls for opening movement of the Waste gate to reduce intake manifold pressure, While the closing movement of the waste gate is always carried out at a rela- 7 Claims.4 (Cl. 60-13) anv too quickly for the controlsystem to maintain jects will be disclosed in the course of the following speciflcation, reference being had to the` accompanying drawings, in which Figure 1 is a schematic showing of an engine, its induction system and a control system for controlling the intakel manifold pressure, my invention beingv shown as embodied in the latter.

Figure `2 is a fragmentary side view of the waste y gate positioning motor, showing one embodiment of my means for controlling or reducing the speed of rotation of the motor in one direction.

Figure 3 is an end View of the assembly of l' Figure 2, Va part thereof being .broken away.

Figure 4 is a view similar to Figure 2 butl showl ing another embodiment of my invention.

Figure 5 is a view similar to Figure 3, but showi ing the apparatus of Figure 4.

Figure 6 is a somewhat diagrammatical showing ofy a further modification of my invention.

Figure 1 of the`drawings illustrates a control system similar to that shown in Figure 1 of the co-pending application of Hubert T; Sparrow, Se-

rial No. 476,797, filed February 22, 1943, but with said system modiiied to embody the present invention'for controlling rate of response of the waste gate motor, thereby limiting the rate of acceleration of the turbine. Inasmuch as the functioning of the system as a whole is necessary of description herein, in order. to understand the need for, and-my means for, control of the rate.

of acceleration it will be described in somedetail. Referring now more particularly to Figure l, there is schematically shown therein an internal combustion enginel, which may be the engine of an aircraft. Air for supportingcombustion in the engine. I0 passes from an intake, not shown in the drawing and conventionally located in the. vleading edge of the wing of the aircraft, through a conduit II, a compressor I2, a conduit I3, an after-cooler I4, a. conduit I5 in which a throttle I8 is located, a carburetor I6, a conduit I1,

a direct-driven compressor 22, a conduit 2|, anv

intake manifold20, and a conduit 23 to the engine I0.

The exhaust gases from the engine I0 pass through a conduit to an exhaust manifold 25,

and thence may pass .through a conduit 26, a

turbine V21, and a conduit'28 to a suitable outlet, not shown in the drawing.

A lconduit'36 connects the conduit 26 with the exhaust gas outlet previously mentioned. In the contact 36 is located a waste gate 3|, whose position determines the proportion of the total exhaust gas of the' engine that passes through the turbine 26. The compressor I2is driven bythe turbine-21 through a shaft 32.

The after-cooler I4 is provided to reduce the temperature of the air leavingthecompressor,

wherein its temperature is increased due to the heat of compression; In the after-cooler, the

Y engine I6 through the shaft 35. Such `a directdriven compressor is usually geared so that itk rotates faster than the engine, and in many 'enginesit is utilized not only as a compressor, but to `distribute evenly the mixture of fuel and air to the various engine cylinders.; Although the compressor `22 is shown as separate from the inl anifold, in most cases it is located within takeY the'intake manifold.

The waste gate 3| is driven by a motor 36;

through a gear train schematically indicated at 38. The motor 36which is herev shown as being of the ldirect current, series Wound type, in-

cludes Van armature 31 and a pair of eld windings 46 .and 4I. As indicated'bythe'legendsin the drawing, th'emotor and the .gear trainare 42,422,1ea i which includes field 4 winding 46. may be traced from the left-hand terminal ofv battery 56 through conductor 5I, switch larm 41,

contact 48,.a conductor 55, field winding .46, armature 31, and ground connections 53 and 54 tothe right-hand terminal of battery 56.

The amplifier 42 has signal 'input terminals 51 and -58, and operates toV selectively energize the windings of the relays 43 and 44 in accordance with the Aphase of an alternating electrical potential applied to the inputgterminals 51 and 58. Electrical energyis supplied to the amplifier 42 fromatransformer 56.

' The phase of the electrical potential'applied to input terminals V51 and 58 is determined by an electrical network of'tlie Wheatstone bridge type, having input terminals l66 and '6 I and out.-Y

Y put terminals 62 'and 63.Y Output terminal 62V so constructed thatwhen field winding 46 is en- Y ergized the motor rotates in a direction to open the waste gate, and when eld winding 4I is energizedfthe motor .rotates in va. direction to close the waste gate. As will bermore fully explained in connection with Figures .2 and 3, the

. motor rotates more slowly when closing the Waste gate than when opening it.

Energization of motor 36 is controlled by an amplier 42. The ampliiier 42 may be of any suitable type, although I prefer to use one of the type illustrated in Figure 2 Vof the copending ap-V plication of Albert P. Uptomserial No. 437,561,

led'April-, 19,42.

'I'he ampliiier 42 includes a pair of relays 43 and 44. Therelay 43 controls the movements of a switch arm with respect to a stationary contact 46, with which it is engaged when the winding of relay 43 is energized. Similarly, the relay 44 controls the movements of Va switchrarm 41 with respect to a stationary contact 4.6, with which it is engaged whenthe winding of relay 44 isV energized. y i e When'switch arm 45 engages contact 46, an energizing circuit is completed for motor 36 which includes eld winding 4I. This circuit may be traced from the left-hand terminal of a battery 50, through a conductor 5I, switch arm 45, contact 46, a conductor 52, eld winding 4I, armature 31, and ground connections 53 and 54 to the right-hand terminal of battery 56.

When the switch arm l41 engages contact 48, an energizing circuit is completed for motor 36 of the bridge circuit. is yconnected through conductor 64 to theinput Vterminal i51 of amplifier 42. Output terminal 63 is connected through conductor 59 and ground connections 49 and 69 to input'terminal 58 of ampliiier42. The input terminals '60 and 6I of the bridge circuit are connected through conductors 66 and 61, respectively, to the opposite terminals of a secondary winding 68 of a transformer 16. The transformers 56 and 10 are preferably connected to theA same source of alternating electrical energy.

'I'he upper left branch of the bridge circuit,

as it appears in the drawing, connects input terminal 66 with output terminal 63. This branch 1 may be traced from input terminal 66 through a conductor 1I, a slider 1.2, a slidewire resistance 13 which cooperates with slider A12, a conductor 12, .a s1ider15,`arslidewire resistance 16 which" cooperates with slider 15, a conductor 11, a por- Y tion of a slidewire resistance 16, and a slider 86 which `cooperates with resistance 18, to the output terminal 63, which is shown as Vbeing located on the slider 66. l

The upper right branch of the bridge circuit, as it appears in the drawing, connects input ter. minal 6I with output terminal 63.V This branch may be traced from input terminal '6I through ay conductor 6I, Aa fixed resistance 82, a conductor 83, a portion of resistance 18, and slider 86 to output terminal 63.

The lower left branch of the bridge circuit, as it appears in the drawing, connects input terminal 66 with output terminal 62. This branch may be traced from input terminal 66 through ico a conductor 84, a xed resistance 85, a conductor 86, a portion of a slidewire resistance 81, and a slider 88 cooperating with .resistance 81, to output terminal 62, which is'shown as being located The lower right branch of the bridge circuit connects input terminal 6I with output terminal 62, and Amay be traced from input terminal 6I through a conductor 96, a fixedresistance 9|,

y ,the compressor I2. This pressure may be measured at any point in the path of the air discharged by the superch'arger, but is preferably measured at a point fairly remote from the supercharger and preceded by a, straight stretch of conduit,

This circuit f so that the effects of turbulence in the flowing air are avoided. In the modification of my invention illustrated in the drawing, I have shown,

by Way of example, that the pressure foroperl atingth'e controller 94 is taken fromv the carburetor I6 throughl a conduit 95 to an expansible bellows 96. The left end of the bellows 96 is xed and its right end is free to move inaccordance with the pressure existing within the bellows. A link |00 is attached to thefree end of th'e bellows 96. y Thelopposite, Vend of the link |00 is 4connected to thefree end of ar second bellows |0I, the interior of which is evacuated. An'intermediatelpoint on the link.,|00 is connected, as by a pin and slot connection (not shown) to the slider 80, which is mounted for pivotal movement about its upper end. The opposed bellows compensate this control or'variav-v r tions in ambient air pressures in a well known manner.

The resistance 16 and the slider 15v together form a compensating controller- |02. The slider is moved across resistance 16 by a velocity responsive control device |03, which may be of any of the shaft 32 but in the present invention this Y is not required.

The slider 12 and resistance 13 together form' a' control point adjuster |20, which is manually operable by means of a knob |2I. The knob |2| is located so as to be under the control of one of the members of the crew of the aircraft, preferably the pilot.

The slider 88 and resistance 81l together for a rebalancing potentiometer |22. 'Ihe slider 88 is moved along the resistance 81 by the motor 36, acting through the gear train 38.

Operation of Figure 1 I When the parts are in vthe' positions shown inA the drawing, the waste gate` is half open, as indicated by the position' of th'e slider 62 at the midpoint of. resistere-3981. The bridge circuit is balanced, so that the bridge output terminals 62 and 63 are at the same potential. Hence no signal potential is applied to the input terminals 51 and 58 of amplifier 42, and neither of the relays 43 and 44 is energized. 4The motor 36 therefore is not energized and the waste gate remains at its half open position.

Now let it be assumed that the pressure of the air in the carburetor I6 decreases, for example, due to an increase in the'altitude of the aircraft. Such a decrease in pressure is transmitted to the interior of bellows 9,6 through the con duit 95. As the pressure inside bellows 96 decreases, the slider 80 is moved'to the left along resistance 18. The potential of sliderl 80, and

.hence the potential of output terminals 63 and 82 of the bridge circuit, and the phase of this potential, is the same Ias that which exists between bridge input terminals 60 and 8|., respectively. AIt may be assumed that the amplifier 42 is so connected that it responds to a potential of this phase applied to itsinput terminals by causing energization of relay43. Energi'zation offre--y lay 43 lcompletes the energizing circuit'.tornio-fy vtor 3B, previously traced, which causes rotation of motor 38- in a direction toclose the wastegate 'and to move the.s1ider 8f8,to the left aliirlgl.r resistance a1. Movement of slider sa tothe j1'e'ft along resistance 81 changes the potential of` o utl-v put terminal 02 toward that of input terminal 60, so that the potential difference between the output terminals 62 and 63'is reduced, At the samev time, movement of the waste gate towards'l closed position causes an increase in the pressure inn |2 c-auses an increase in the compression ratio between the output pressurer and the input pres-V sure of the compressor. 'I'h'e intake manifold pressure is therefore increased, and the increase vis transmitted'through the duct 95 to the interior of bellows 98. 'I'he increased pressure inbellows` 86 moves the slider 80 back to the right along resistance 18. As soon as the sliders 80 and th'esame, thesignal potential impressed on the input terminals of amplier 42 is reduced to zero, and the relay 43 is therefore deenergized. The motor 36 then stops, with the waste gate remaining in a newr position. It will be readily understood that the distance movedby thewaste gate is .proportional tothe pressure drop which initiated the movement, the proportion being determined by the ratio between the potential` r drops per unit length' along the resistances 18 and 81. f

In a similar manner, an increase in the pressure of the air supplied by the compressor |2 causes a movement of slider 80 to the right along resistance 18which changesthe potential of output terminal 63A with respect to that of output I -terminal 62 in a sense opposite to that encountered under the conditions previously described,

The alternating signal impressed on the input.

terminals yof amplifier 42 is thenof a phase opposite to that vwhich was previously impressed on .its input terminals. The amplifler`42 responds to this new signal potential by causing lenergiza'- tion of the winding of relayr44. This operates phere, thereby reducing the pressure in the ex;

haust manifold, and reducing the speed ofA the turbine and compressor which results in a reduction of the intake manifold pressure.

By manipulating the variable resistance 93, the total resistance between the terminals of resistance 81 may be varied, and hence the. total po.- tential drop across the resistance 81 is likewise varied. Since the total potential drop is varied,

thepot'ential drop per unit length of resistance 81 is changed. Therefore, by changing the vari-v able resistance 93, it is possible to adjust the distance through which the slider88 mustmove of that of resistance 18.

The control point adjuster |20 may be manually operated to increase or decrease the resistance in the upper left branch of the bridge cir-v cuit. The setting of controller 20 determines the particular position at which the waste gate is stopped for a given value of pressure existing in the carburetor I8. It may therefore be used l to set the value of pressure in the carburetor ,|6 which thesystem is to maintain.

in the system operates to increase the pressure selected. i The slider of the compensating controller |02 is moved to the right-along the resistance 16 by action of the control device |03 whenthe vev locity of the turbine 11 and compressor l2 approaches a predetermined safe value and as this action takes place the increased value of the resistance 16 inserted in the upper left branch of the bridge circuit causes a response ofthe amplifier 42 and motor 36 to drive the waste gate 3| It may be desirable for the pilot to select the y supercharger discharge pressure within a range of from 15 to 32 inches of mercury, After such a value of discharge pressure has been selected, it is usually desiredthat the system maintain that pressurewithin a range of one inch of mercury .more or less than the selected value regardless of the altitude of the aircraft. In order to produce these results, resistance 9 3 should be adjusted so that the eiect of resistance 81 is 2/1'1 In other words, the slider 80 moves from one end to the other of resistance 18 as the pressure at the carburetor varies over a range of 1'7 inches, and the slider 88 is to move from one end to the other of resistanceV 81 as theslider 82 moves through a distance corresponding to a pressure change of two inchespf mercury. By manipulation of resist- `ance 93, the total resistance between the terminals off-resistance element 81may be varied, so that the operating differential of the system may be varied.- The operating differential may be defined as the variation in pressure at the carburetor needed to cause movement of the waste gate from one end to the other of its range.

`Since`the controlpoint selector |20 must -vary' the relationship between-the control potentiometer 94l and the rebalancing potentiometer |22 overa verywide range of positions of the slider 80, and a relatively narrow range of positions of the slider 88, the resistance of element 13 should toward open position. The result is a tendency towardopposing the unha-lance of the bridge circuit Whichis causing movement of the waste gate towards closed position, and to such extenl'I that the waste gate'cannot be .closed sufliciently tol build up the velocity of the turbine and ,com-

pressor beyond a,- safe maximum, even though closing to this extent may be'\c\alled for by the pressure sensing controller 94. *The controller 02 thus operates as a velocity limit control.

Whenthe turbine 21 is accelerating, due to a movement of "thewaste vgate 3| toward closed position, the turbine may'continue to accelerate after the pressure controller 94 has been satisfied, because of theinherent lag in the system between the carburetor I6 where the pressure sensing take-off is located, and the exhaust manifold,

and because ofthe inertia of the turbine and compressor. If such an acceleration of the turbine continues after the vpressure controller 94 'has been satisfied, it causes an abnormalincrease in the pressure of the air supplied by the supercharger, which acts through the controller 94 and the system which controls motor 36 to cause a movement of the waste gate back toward its open position. This movement of the waste gate toward open position in turn causes a decrease in the pressure of'the air supplied by theV compressor, and a hunting condition results in which the pressure being controlled continuously oscilbe Vsuch that its ltotal unbalancing effect on the.

bridge circuit is comparable to that of resistance 18. Since the compensating controller |02 may be required, under certain conditions as will presently appear, to completely overcome the effect of the-main controller 94, resistance 16 should also be such that lits `unbalancing effect may be comparable to that of resistance 18.

If the proportion of resistance 13 connected in the upperfleft branch of the bridge circuit is tain.

lates about the value which it is desired to main- .'I'he establishment of such a vhunting or overshooting condition is prevented by the provision of-.means for closing the waste gate slowly enough to limit the rate of acceleration of the turbine 21 and compressor |2, as will now be described.

` Figures 2 and 3 In Figures 2 and 3 an end portion of the motor 36 is shown from which extends a shaft |23 l driven by the motor and which may bel the shaft connected through the gear train 38 to the waste increased, then the resistance of the upper left branch is increased in proportion jto the resistance of the upper right branch. An increase in resistance element: 13 therefore has the same unbalancing effect on the system as an increase in the intake manifold pressure. Such an increase causes the waste gate to move towards open position, thereby reducing the intake manifold pressure and causing the slider 80 to move to the left along resistance 18. it may be stated that an operation of control point adjuster |20 to increase the proportion Of resistance 13 connected in the system lowers the value of intake manifold pressureselected, and ,an operation of controller 20 to decrease the proportion of resistance element 13 connected gate 3|, o r an opposite extension thereof. IIhe latter arrangement is diagrammatically shown inv` Figure 1. An eccentric |24 is freely journaled on the shaft- |23 and is connected to rotate therewith', in one direction of rotation thereof, by a self-energizing unidirectional clutch or ratchet means comprising, as here'sh'own, a snubbing spring |25. This spring |25`is a coil spring and frictionally engages the shaft |23, with one end connected by an eye |26 to a pin |21 carried by the eccentric |24. The other end |28 of the spring |25 is loose as shown. -In action the shaft A|23 may turn freely and independently of the ,eccentric |24 and spring |25 in one direction but,

when the direction of rotation of the shaft is reversed, the spring is tightened bythe frictional engagement of the shaft surface vwith the spring coils, causing the constriction of these coils into gripping engagement with the shaft. The eccentric is then caused to rotate in this directionv along with the shaft as will be understood. The en-y l gagement and disengagement of the springis entirely automatic.

The eccentric |24 i operates a light lfollower member or friction disk |29 of fiber, Bakelite or similar material which operates betweena pair of comparatively heavy weight members or metallic inertia disks |30 and |3 I. The three disks |29, |30 and |3| are arranged in frictional surface engagement and are pivoted near one edge on .a pivot screw |32 fastened, as at |33, to the end of the motor housing. The friction .diskl |29 has a central` opening |34 elongated in one direction to clear the eccentric |24 and adapted at itsv sides to ride the same (Figure 3) so that asthe eccentric rotates this disk will be oscillated about the axis of the pivot screw |32 as will be apparent. The inertia disks |30 and |3|, on thelother hand, have large central openings |35 which will ,clea the eccentric by some distance. I f y At a point diametrically opposite to the pivot screw |32, a fastening screw |36 is passed through the assembled disks |29, |30 and |3|, near their edges, and it is provided with a nut |31 and-lock washer |38. The friction disk |29 has a clearance opening |39 which clears thisscrew `|36 at all times.

Operation of Figures 2 and 3 In use the motor 36 is so connected to the waste gate 3| that the shaft |23 rotates free of the eccentric |24 when the waste gate is being opened. The disks |29, |30 and |3| thus are not oscillated while the waste gateis being opened and hav no effect on the operation of the motor. .1 l

When the lmotor is' reversedto drive the wast gate 3| toward closed position, to speed up the,

operation of the turbine 21 and compressor |2,.

the snubbing spring |25 connects the eccentric |24 to shaft |23 causing the eccentric to=rotate. This action swings or oscillates the disks |29, and |3| about the pivot |32. At low'speeds, as when the motor 36 first begins to rotatein this direction, the three disks will oscillate as aunit and hence will have little or no'effect onthe operation of the motor. As the speed builds up to the point at which the waste gate 3| would ordinarily be. closed so rapidly as to cause over acceleration of the turbine and compressor, and hunting or overshooting as previously described, the action changes, however. Due tothe inertia of the heavier metal inertia .disks |30 and |3| they are then unable to follow the rapid oscillationof the friction disk 29 which then begins to slipy or vibrate independently of ,the inertia disks. The drag or friction between the contacting surfaces of the disks, and the degree ofsuch slippage therebetween, may be readily adjusted by loosening or tightening the nut |31 by which the disks are `held together,

The slippage of the disks as described serves to dissipate a part of the power or energy developed by the motor 36 and as a result causes it to run at a reduced speed. The `motor thus actually runs at a higher speed when opening the waste gate, than when closing the same, and hence achieves the desired effect of preventing over acceleration of the turbine and compressor.

Figures 4 and 5 identical .with those shown in Figures. 2 and 3 v they .are indicated byv corresponding v reference numerals. 'f

In lieu, howevenvof the followerand inertiay disks I provide inthis apparatus a single oscillat! ing or follower member designated 'generally-.at |40 which comprises a hollow casing of drinn-:.-

like shape having sides |4|-|42 and 'an' annular rim |43. A central slotted opening |44 is provided, within an annular centervwallor hub |45,

te eopperate with the eccentric |24 se thatiretef tion thereof' will oscillatettl'iisgmember ,I 4|lairiou`t,vv 'Y a pivot screw., |46 disposed near one edgeg and, Y secured at lill/tothe end of the motor housing,V

The hollow interior of the follower member|40 is partially filled with metaliilings, sandor-othl'er heavyv granular material, as shown at `|40,and

one ofthe sides |4| or |42 may obviously be' made removable 'l for `the purpose of thus` fillingfftlfe':

member.Y Operation0.1Figuresi4anci5;` {.g-

Here againthe motor 36 is so arranged thaty tion, drives the eccentric |24 through the snubbing action of the spring |25 and then l'oscillates the follower member |40 about 'the `pivot|46.

This oscillation of the follower member |40 shiftsy its granular contentsv |40'causin`g, the'sha'pe of:

the mass thereof to be changed. This has'a damping effect which again dissipates a part ofthe energy produced by the motor Acausing it to. run

at ya slower rate inthis directionand closing the waste gate in a more gradual manner;H In thiscasethe damping eectof the'v shifting maslsofmaterial in the follower member |40 "ble-M` gins".i 'soon as thelmotor'starts rotating lin this directionsnd' increases es the meter deyelcpeI power. tjwill abe evident, therefore,- that the waste gate will be closed very gradually andj'witliout any possibility of causing over acceleration of the turbine -and'compressor with the un"A esirable effects thereof. j,

1 f Figure 6 y A .4 In this view I have shown the meter as as driving afshaftv |49 which is adapted to be 'operatively connected vto -the waste vgatey 3|'. Two stages'of speed reduction gears are interposed between themotorland shaft |49, one stage opervating''whe'n' theA motor rotates in one direction 'whilethe` other stage operates when the motor is' reversed. Reduction gears are ordinarily used in connection with such motors and this apparatus involves merely the addition of another stage with suitable clutch means as will now be described. 1

A pinion |50 on the shaft |5| of the motor 36 meshes with and drives a gear |52 on'a countershaft |53. This counter-shaft carries a low. speed A self-energizing clutch spring |56 is provided for connecting the low speed pinion |54 to the countershaft |53 when the same rotates in one direction, and a similar, but oppositely acting, spring` |51 is provided for connecting.the high speed pinion |55 tothe counter-shaft when it rotates in the opposite direction.` These springs |56 anda.

|51 operate exactly as .does the spring|25 shown in Figures 2-5 and previously described.

'gate 3| isL beine nosed, new;

meshing w1.

enemies.

IBN innion. y IGIjqgearfIBl 'pinion |64 fand;y gear I6 When*I the motor ,is -reversedtoclose-fthe t, .,110 rotatable ibyf': the? motori in opposite directionsgandf- 1 the,il gears arefsdj arranged that; :when the f motor I SIAther-clutch `spring'l "I 51? willbe tightenedl c'al'usin the hi'gh speed ldriveflcginion'.V I51to rotatel The shaftf :I 49 Vis'v then '1 rotate at a 1 vcertain :speed 'proportional "to, that waste-gate the-spring I56fwil1'betightenedestabl lisl'iirig-A -az-driving connection"` to` the low i speed Y l drivepinien-,I M;whien-theny drivesl the shaft .149- `tifnfoughtheelc'aw "speedA gear f I 58,:v pinion- I 6 I, "gear the difference Yin relative 'pitchA` diameters' of-` 'the hi'glif"and-lowj speed' pinions andgears as' clearly Asliciwngthe f shaft I 49 will: liin this; case be driven atrafslowersspeedf relative' to` that of the motor,- causing-the wastev gate toV be closed"- gradu'ally inv the,desiredV manner.

WiiI'e'QI-.hve shown my* invention in con-l neetion with` an: internal vcombustionengine,- 'it is generally? applicable tov other forms of Vcombustion-engines; l In the' claimsthe term`r combustion 1 engi'nefis` toib'e" construed asv sumciently broad to cover-.othery forms ofengines such; asa ietf the structure as disclosed,fprovided such modirl`V appendedjclaims: Having now therefore` vfully illustrated; and`described:fmy invention;` .what I claim?! yto; be new land desire` to protect by-.Letters Patentis: 1

11.r Inlcombination, a combustion engine having 1 aicompressor* for 'supplying' air vto the `intake manifoldof: thej engine and a turbine powered by exhaust gasesfromfthe' engine for yoperating the compressor-,1 vmeans for adjsting the operating speedofithe; turbine vand compressor to thereby control the compressing effect of the latter, and motonmeans for yope-rating saidadjusting means ttincre'asev` andz decrease .the operating .speeds` ofV their-turbine rand; 'cornlzv'ressorgy saidy ymotor means being"v operative toeincrease the operating speeds afs.' e

sp l

2 .Inv combination, acombustion engine having a3. compressori for.A supplying air- `to the intake manifldi-'of the 11 engine Land= a :tnrb'ine poweredbyljexhaust. gasesfrornthe .engine 1 for operating tl'xellgcompressor,v means for adjusting? the operati ingfspeedoffthe lturbine' andcompr'essor-"to therebillA control f1 tl'ife compressing elect'. of4 the. latter,

reversible motor means-gior operating said; speed adjusting means.A -and brake means for. limiting vmo're' gradual; rate than`v it?V decreases"` these ngine.v In*general,` it g `is to `lbe' understood tlatiayf suitable'.y modifications may be.l made infl cations comewithin the spirit and scopefoffthe 1 theS-speefofffthe: motor whileA operating: said?`v speejdzfv ladjusting means iin oneV direction! whereby the sp'eediofthe .turbine andv .compressor willA be increased-ai;vv aY slower ratev than. it is `decreased.` 3. A-system for` controlling .the pressure of tbe.'-

air; vsupplied to the i intakev manifold of'l a combustion lengine having.' acompressory forisupply f' ing the air lto'Y the f manifold: comprisingrin' com'` Vbination; a. memberf adjustable,` in `opposite :directions for.I increasing `anddecreasingv the y speedof operation off the compressorand thereby acontrolling thecompressing-efect ofthe compressor, reversiblemotor'means rotatable in one direction-r to adjust the saidv member to decrease the compressor.. speed. and rotatable in the oppositedirec-- tion1to..adju`st'said member` toincrease the-com? presser-speed, and separate gear `reduction stages?- operativelyconnected between the motormeans andr said member whereby .the memberwill 'rbecv 'adjusted' slower ywhen increasingI the. compressor v speed .than when decreasing the compressor,

speed.

4..' A system4 for controllingI the vpressure01E/the -f air suppliedto the intake'manifold'of a combustion i engine having -a compressor :for f supplying the'.

air tothe manifold, comprising in combination;`

a memberl adjustable in v'opposite` directionsV for 'v increasing and .decreasing lthe *speedsof-V opera-#f tion of vthe compressor. andl thereby r controlling'. the compressing .effect vof the compressor, 'revers-1 ible-.motor means rotatable'ini onedirectiontov` adjust the said member to decrease.-th'e compressorfspeed andy rotatable inv the opposite direction to adjust saidmember to.4 increase the compressor.,speed, andI high'v and lowf speedv reduc- Y tion geari stages `selectively operative` as theg-mo- .l tor means reverses in direction and connected: to',- saidadjusting .member whereby thefcompressor speed wi11- beincreased by ther'slowlspeed. gear`r stage anddecreased by the high' speed. gear stage. 5. A system for controlling thelpressureof the air `supplied forcombustion in' a combustion en gine having `a compressor'v for supplying theair,

comprising in combination, .oppositely vadjust' :ablegmeans for varying-the operating-,speed of" the compressor andithereby controllingthe compressingfeftect thereof, areversible motor rotat" able -in one direction for adjusting the said means to lincrease the compressor speed androtatable in theiopposite` direction for rvdecreasingcompres-l sor speed, brake means operativev -tol lmitthev speed ofthe motor, and automatically operatingv clutch meansfor connecting said brake means to themotor when it rotas in the direction for increasingcompressor speed. n

. 6. In combination a combustion engine` having a `compressor for supplying air to the intake manifoldof the engine and a turbine powered by exhaust gases from the enginelfor operating .the'compressor, means for adjusting the operating speed .of the turbinerjand compressorto thereby control the compressing effect ofl the` latter, reversible motor means-for operating. said adjustingv means, and Ameansfor causingsaid motor means to run slowerinl thedirection/'in Y whichthe operating speedsof the turbine and compressor vare increased thanv` in the,v direction" iniwhich said operating speeds are decreased;Y

7. A systemfor controlling ther pressure ,of` the airsupplied to the intakev manifold of a com` bustionengine having aucompressor forsupplying the 4air Vand a turbine powered bygexhaust gases from the engine for operatingY thecom pressor, comprising in combination, means" forV ladjusting the operating'speed of theturbine and compressor to thereby control the compressing'.- eifect of the latter, reversible-electric motor means for operating saidspeed adjusting means;

said' motor meansmormallyt'ending to run at the-same speed in both directionsand means operatively connected to and driven by said motor means for limiting the speed thereof when the adjusting means is being operated in a direction to increase the' operating speed of the turbine and REFERENCES CITED The following references are of record in the le ofthis patent; v

y Number UNITED STATES PATENTS i Name Date Berger et al. Oct. 20, 1925 Moss July 23, 1931 Berger May' 19, 1942 Lazich Feb. 19, 1935 Connell Feb.17, 1942 Thompson Sept. 1, 1908` Flanders July 6, 1926 Meunier Jan. 9, 1934 Buckley Sept. 17, 1940 Grun Mar. 22, 1921 Sherbondy July 13, 1920 

